IB Physics IA: Ideas and How to Score High

A good IB Physics IA idea is a narrow, testable question you can answer with equipment you can actually access — not a grand theory. The IA is marked out of 24 against five criteria: Personal Engagement, Exploration, Analysis, Evaluation and Communication, each worth 6 marks, assessed by your teacher and externally moderated.

The five criteria are Personal Engagement, Exploration, Analysis, Evaluation and Communication, each capped at 6 marks for a total of 24. Your teacher marks it first; the IB then moderates a sample of scripts from each school to keep standards consistent across the world.

The IB Physics guide caps the written report at 3,000 words, excluding tables, graphs, equations, citations and the bibliography. There's no minimum — but a report well under 2,000 words usually means the Analysis or Evaluation section hasn't been developed enough to reach the top mark band.

A 7 in Physics almost always sits alongside an IA scoring 20+ out of 24, with Analysis and Evaluation the strongest sections — the two criteria most students under-develop. That means real uncertainty propagation, a linearised graph with gradient uncertainty, and an evaluation naming one specific systematic error rather than 'human error'.

The three mistakes I see most as an examiner: treating 'human error' as a genuine uncertainty source, collecting only 3–5 data points across a narrow range, and writing an Evaluation that repeats the Analysis instead of critiquing the method. Any one of these tends to cap the overall mark around 15–18 out of 24.

According to the IB Physics guide (first exams 2025), the Internal Assessment is worth 20% of your final grade at both SL and HL — the same proportion as Chemistry and Biology. Because Physics has fewer total assessment components than some Group 4 subjects, a weak IA can still shift a final grade boundary by a full mark.

HL topics that score well tend to involve more mathematical modelling: damped SHM with a magnet and coil, RLC circuit resonance frequency, diffraction grating wavelength with a laser, or terminal velocity in a non-Newtonian fluid. The bar for HL isn't a harder experiment — it's a more sophisticated Analysis, often involving log-log linearisation or non-linear curve fitting.

Solid SL topics include resistivity of a wire versus temperature, the period of a pendulum versus length, projectile range versus launch angle, or spring constant versus coil temperature. These give a single clean independent variable, straightforward linearisation, and equipment most school labs already have.

Yes — the IB Physics guide explicitly allows simulation or modelling-based investigations, but you need to justify why a hands-on experiment wasn't feasible and show genuine manipulation of the model's parameters, not just running default software settings. A purely observational report on someone else's simulation won't score well on Personal Engagement.

Start with the phenomenon you're curious about, then narrow it to one measurable, changeable variable and one measurable outcome. A research question like 'How does the amplitude of a swinging pendulum affect its period?' works because both quantities are directly measurable with equipment you can access.

Yes — the format, word count and marking criteria are identical for SL and HL Physics IAs; there's no separate rubric. The difference is expectation, not structure: examiners look for HL reports to show more mathematically demanding Analysis, since HL students study extra content like the option topics and additional core material.

There's no fixed IB-wide date — each school sets its own internal deadline, usually in the first term of DP2, so teachers have time to mark and moderate before the IB's upload window. Schools must submit final IA marks to the IB via IBIS several weeks before the May or November exam session begins.

The most useful thing you can do is protect their time — the IA needs several separate sessions of data collection, not one weekend rush — and help them stick to a realistic timeline set against the school's internal deadline. Leave the physics content to your child and their teacher; your job is logistics and encouragement.

Usually not. Most successful IAs use a phone's slow-motion camera, a ruler, a stopwatch and equipment already in the school lab. Occasionally a student's chosen topic needs a specific sensor or data logger — schools generally provide these, so it's worth checking with the Physics teacher before buying anything.